Cylinder head oil leak help.

[matchstick321]

Well I just did my first automatic to standard conversion on my 79 k20. And after driving it for a couple miles and then bringing it back and puting it in my garage I looked underneath of it and found that it was leaking...
I fingered arround back behind my engine and as far as I can tell it's leaking from the back of the cylinder head.
I'm wondering if I should clean it up back there and try to shove some silicone in the leaking area? Or if I should just take the engine apart and replace the head gaskets?
It's a 350. So just wondering from any one with experience if it's hard to take the engine apart, how long it would take me to to the whole project. Or if you have tryed siliconing it, and if it worked?

[85sierraclassic]

are you sure it insnt the oil sending unit on the back of the motor and the intake gaskets might have blown in the back but would say pry broke the oil sending unit when you had the trans dropped or back in if the motor leaned back when you pulled the trans.

[matchstick321]

That would make sence 'cause it did lean back quite a bit when the tranny was droped I will go check it out and get back to you on that!

[matchstick321]

Nope, that wasn't it. It's definatly a gasket... I can't quite pin point where the leak is at though, my engine is so dirty/greasy. Maybe I should take it apart anyways just to clean it a paint it. haha

[ozark]

It shouldn't be a head gasket. Check and see if a valve cover flange didn't get bent while you were changing the trans. Also check and see if the distributor didn't crack in the area around the shaft where it goes into the intake manifold.

[dugvera@gmail.com]

Get under it with a flashlight while its running and wait. Id find the leak before pulling anything apart. Just sayin.

[matchstick321]

Originally Posted by ozark

It shouldn't be a head gasket. Check and see if a valve cover flange didn't get bent while you were changing the trans. Also check and see if the distributor didn't crack in the area around the shaft where it goes into the intake manifold.

Well I have one of those huge distributors so it's prolly the more likely out of the two. I'm going to be mad if it is I'm tired of spending money on this truck...

[dugvera@gmail.com]

Thats kinda what I was gettin at. Rather than spend any money first know the what the issue is. There is a very good chance its not going to cost alot. Could be a rear main seal though???? Parts not expensive but the labor.
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[matchstick321]

Oh Yeah, Definatly I always make sure of things before I spend my money!

[matchstick321]

Well it's not the distributor shaft. I'm leaning toward my head gasket theory. I took a rag and some starter fluid and cleaned up on the back of the engine block as best as I can. I'm waiting for my battery to charge so I can fire it up and try to see where it is leaking from. And then we will see where it's leaking from. It's about a half a quart low on the dip stick. So I'm wondering if it will still have enough to even leak at all?

[Weasel Diesel]

What may have happened is that when the engine leaned back, it may have cracked the brass adapter that the oil sending unit screws into, down near the block from coming into contact with firewall.

[matchstick321]

No it's not that. I can see all of that stuff clearly but it's leaking from somewhere behind the block where I can't see. That's why I'm thinking its a head gasket. But what I can't figure out is why it wasn't leaking untill after I started puting the new tranny in it. It sat in my garage for about a year and a half and didn't leak a drop I had even started it up a couple times. It wasn't until I bolted a bell housing down there so I could tell where to bolt my clutck linkage an everything to the frame that it started leaking...

[Weasel Diesel]

Problem is... there is no oil ports thru a SBC head gasket. It drains thru holes that go straight into the lifter gallery. Thats why I am skeptic on a head gasket.

[matchstick321]

Yeah I wish I could see back there, I could prolly figure it out faster if I could.

[dugvera@gmail.com]

Valve cover
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[matchstick321]

Originally Posted by dugvera@gmail.com

Valve cover
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I don't think so none of that came in contact with my firewall. Plus it's leaking quite a bit. I wouldn't think it would leak to much out of the valve covers. Plus I could see if they were leaking.

[dugvera@gmail.com]

Huh. Valve covers dump quite a bit of oil. Let me ask you this.... is it a high pressure leak? I guess im having a real hard time swallowing the head gasket leak.
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[dugvera@gmail.com]

Is there a oil pressure gauge hooked up to the block there by the distributer? What kinda line? Would it be impossible to get pics? We might be able to see something overlooked? Im tryin to help bro.
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[matchstick321]

I'm guessing that it is high pressure. 'cause in the time that I have changed the oil which was yesterday, it's leaked a fairly large puddle of oil on my garage floor. But then again it still kinda leaks when the truck is not running. So I really wouldn't know... In case you can't tell I'm kind of green in the mechanics section.

[matchstick321]

Originally Posted by dugvera@gmail.com

Is there a oil pressure gauge hooked up to the block there by the distributer? What kinda line? Would it be impossible to get pics? We might be able to see something overlooked? Im tryin to help bro.
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I know you're trying to help, and I appreciate it! I can be really hard to work with. I do this kind of stuff better in person. haha Uhm I will go take a look and see what I can find and get back to you on that I have and oil pressure gauge but I have no idea where on the block it is hooked to... Your prolly looking at this now shaking your head in disapointment. haha

[dugvera@gmail.com]

You'd know if its under pressure like the gauge connection it would pump alot of oil out quickly. 20 psi at an idle is alot of oil moving! Like spraying a stream style leak. If you had water spraying out or something crazy id say head gasket. Did you by chance change anything about the crank case breathers? or vacume lines?
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[matchstick321]

Nah it's definatly not spraying out I'd say gravity is at work on this one and no I have not done anything to the vacume lines or crank case breathers. Like I've said I can't see back there all I can do is finger arround back there.

[matchstick321]

Omg I am sorry guys... I did what I should have done in the first place I fired it up and crawled back there while it was running and found out it was actually leaking out of the bottom of the oil sender... I've never heard of this before but it looks like there is some sort of seal on the bottom of it that had been broken...Looks like 85sierraclassic had it right ON THE FIRST POST!... I'm so disapointed in myself... Again I'm really sorry! =\
And I thank ALL of you for your help!

[dugvera@gmail.com]

Cool deal. No one was shaking their heads. We're all here to learn.
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[matchstick321]

Haha well thanks! Nice to know this forum is full of cool dudes like you! But there are the few retards like me that sneak in here too! lol Yeah learning more about my truck and what I can do to improve it is the only real reason I joined this forum, good to know there is plenty of knowlege to be found here!